title: Adaptation of maize source leaf metabolism to stress related disturbances in carbon, nitrogen and phosphorus balance.
abstract: BACKGROUND
  Abiotic stress causes disturbances in the cellular homeostasis. Re-adjustment of balance in carbon, nitrogen and phosphorus metabolism therefore plays a central role in stress adaptation. However, it is currently unknown which parts of the primary cell metabolism follow common patterns under different stress conditions and which represent specific responses.
  
  
  RESULTS
  To address these questions, changes in transcriptome, metabolome and ionome were analyzed in maize source leaves from plants suffering low temperature, low nitrogen (N) and low phosphorus (P) stress. The selection of maize as study object provided data directly from an important crop species and the so far underexplored C4 metabolism. Growth retardation was comparable under all tested stress conditions. The only primary metabolic pathway responding similar to all stresses was nitrate assimilation, which was down-regulated. The largest group of commonly regulated transcripts followed the expression pattern: down under low temperature and low N, but up under low P. Several members of this transcript cluster could be connected to P metabolism and correlated negatively to different phosphate concentration in the leaf tissue. Accumulation of starch under low temperature and low N stress, but decrease in starch levels under low P conditions indicated that only low P treated leaves suffered carbon starvation.
  
  
  CONCLUSIONS
  Maize employs very different strategies to manage N and P metabolism under stress. While nitrate assimilation was regulated depending on demand by growth processes, phosphate concentrations changed depending on availability, thus building up reserves under excess conditions. Carbon and energy metabolism of the C4 maize leaves were particularly sensitive to P starvation.
authors.affiliation: Department of Biology, Division of Biochemistry, Friedrich-Alexander-University Erlangen-Nuremberg, Staudtstr, 5, 91058, Erlangen, Germany.
authors.forename: Urte
authors.initials: U
authors.lastname: Schlüter
authors.forename: Christian
authors.initials: C
authors.lastname: Colmsee
authors.forename: Uwe
authors.initials: U
authors.lastname: Scholz
authors.forename: Andrea
authors.initials: A
authors.lastname: Bräutigam
authors.forename: Andreas P M
authors.initials: AP
authors.lastname: Weber
authors.forename: Nina
authors.initials: N
authors.lastname: Zellerhoff
authors.forename: Marcel
authors.initials: M
authors.lastname: Bucher
authors.forename: Holger
authors.initials: H
authors.lastname: Fahnenstich
authors.forename: Uwe
authors.initials: U
authors.lastname: Sonnewald
mesh_terms: D000222:Adaptation, Physiological / Q000235:genetics; D002244:Carbon / Q000378:metabolism*; D020869:Gene Expression Profiling; D006706:Homeostasis; D009584:Nitrogen / Q000378:metabolism*; D010758:Phosphorus / Q000378:metabolism*; D010788:Photosynthesis; D018515:Plant Leaves / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D036226:Seedlings / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D013312:Stress, Physiological / Q000235:genetics; D013696:Temperature; D003313:Zea mays / Q000235:genetics / Q000378:metabolism* / Q000502:physiology
chemical_list: D012333:RNA, Messenger; D010758:Phosphorus; D002244:Carbon; D009584:Nitrogen